Difficulty of developing an independent (not forked) server emulator?

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How hard is to develop an independent (i.e, not based on another) WOW server emulator?

Over the last years, decompilers have appeared that can speed up the development, as one could decompile the client to figure out the protocol, but some things are heavily obfuscated (like the Battle.net protocol, apparently). Also Blizzard has made it hard to develop a emulator for expansions after WotLK, e.g by introducing a phasing system in Cataclysm and in WoD, making a Battle.net server mandatory, introducing a new container format (CASC) and reworking the phasing system (removing the phase names).

Furthermore, all emulated servers must be populated with maps, DBCs, and others to prevent the world from being "empty".

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The only non-TC based server emulator that I found for WoD or later expansions, is Mangos Five, but the repositories for that contains just a dummy emulator, (only the files required for compilation). It does not emulate anything (at least for now).

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And finally, it is possible to write server emulators in programming languages other than C++, like Ruby, PHP, Go, C#, or even C? Because I have not found any WOW server emulators in these programming languages either.